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digitalmars.D.learn - readf

reply nascent <jesse.phillips eagles.ewu.edu> writes:
Ok, supposedly readf grabs console input from the user. I found this 
archive 
http://www.digitalmars.com/d/archives/digitalmars/D/learn/1900.html that 
wasn't much help. So my questing is how do I use it? Feel free to skip 
my guesses as to how it works and just tell me.

I will not explain how I think I am supposed to use it. readf("Bla %s 
...", var, ...) The first way is "Bla " is printed to the screen and 
waits for %s input. The second is that it would look at the input string 
and grab %s.

Example-ish

int integer;
char character;
char[] string;

// Option A
readf("Enter an Int: %d, a character: %s and a string %s",
	&integer, &character, &string);

// Option B
readf("I like %s, my favorite letter is %c, and I have %d meals a day.",
	&string, &character, &integer);


Option A would look something like this: user input is in {}
Enter an Int: {6\n}
a character: {T\n}
and a string {Fly away I tell you.\n}
(integer would be 6, character T, and string Fly away I tell you.)

Option B would look:
{I like cheese, my favorite letter is q, and I have 3 meals a day."\n}
(integer 5, character s, string cheese)

--Jesse
Feb 17 2006
parent reply Sean Kelly <sean f4.ca> writes:
nascent wrote:

 Ok, supposedly readf grabs console input from the user. I found this 
 archive 
 http://www.digitalmars.com/d/archives/digitalmars/D/learn/1900.html that 
 wasn't much help. So my questing is how do I use it? Feel free to skip 
 my guesses as to how it works and just tell me.


readf is to scanf what writef is to printf :-)  If no format strings are 
supplied, default formats will be chosen for the supplied parameters. 
I'm not sure which version you're using, but here's an example pulled 
from the unit tests in my original version:

int n, i; double x; char name[50];

n = sreadf( "25 54.32E-1 thompson", "%d%f%s", &i, &x, &name[0] );

Alternately, you can do away with the format string altogether and it 
will expect the default formats:

int n, i; double x; char name[50];

n = sreadf( "25 54.32E-1 thompson", &i, &x, &name[0] );

For information on the formats accepted, check the C spec, as readf was 
written to be fully compliant with scanf in C (plus additional support 
for D-specific types).


Sean
Feb 17 2006
next sibling parent Sean Kelly <sean f4.ca> writes:
By the way, my original readf implementation is available here:

http://home.f4.ca/sean/d/stdio.zip

It requires the included utf module, which is simply a modified version 
of std.utf to accept delegates as a source/destination for encoding and 
decoding.


Sean
Feb 17 2006
prev sibling parent reply nascent <jesse.phillips eagles.ewu.edu> writes:
Well, I must not be importing the correct library. I get that sreadf is 
undefined. Isn't it in stream?

import std.stdio;
import std.stream;
import std.c.stdio;

void main() {
	int n, i; double x; char name[50];

	n = sreadf("25 54.32E-1 thompson", "%d%f%s", &i, &x, &name[0] );

	writef("%d", n);
}


Sean Kelly wrote:

 nascent wrote:
 

 Ok, supposedly readf grabs console input from the user. I found this 
 archive 
 http://www.digitalmars.com/d/archives/digitalmars/D/learn/1900.html 
 that wasn't much help. So my questing is how do I use it? Feel free to 
 skip my guesses as to how it works and just tell me.


 
 
 readf is to scanf what writef is to printf :-)  If no format strings are 
 supplied, default formats will be chosen for the supplied parameters. 
 I'm not sure which version you're using, but here's an example pulled 
 from the unit tests in my original version:
 
 int n, i; double x; char name[50];
 
 n = sreadf( "25 54.32E-1 thompson", "%d%f%s", &i, &x, &name[0] );
 
 Alternately, you can do away with the format string altogether and it 
 will expect the default formats:
 
 int n, i; double x; char name[50];
 
 n = sreadf( "25 54.32E-1 thompson", &i, &x, &name[0] );
 
 For information on the formats accepted, check the C spec, as readf was 
 written to be fully compliant with scanf in C (plus additional support 
 for D-specific types).
 
 
 Sean
Feb 18 2006
parent Sean Kelly <sean f4.ca> writes:
nascent wrote:

 Well, I must not be importing the correct library. I get that sreadf is 
 undefined. Isn't it in stream?


Oops, I was talking about an extension I wrote that's not in Phobos.  I 
think std.stream has a similar function as a part of the IStream class.


Sean
Feb 18 2006